Automatic ticker-receiver.



J. H. HAMMOND, Jn. AUTOMATIC TIOKEB RECEIVER.- nrmoumn FILED AUG. 24,1912.

1,093,3 0, Patented June 2, 191:1

WITNE88E8 INVENTOR Y JOHN HAYS HAMMOND, 33., OF GLOUCESTER,MASSACHUSETTS.

AUTOMATIC TICKER-RECEIVER.

Specification of Letters Patent.

Application filed August 24, 1912. Serial No. 716,863.

To all whom it may concern Be it known that I, JOHN HAYS I-IAM- Morn), Jr., a citizen of the United States, residing at Gloucester, in the Stateof Massachus tts, have invented certain new and useful Improvements inAutomatic Ticker-Receivers, of which the following is a specification.

My invention relates to improvements in receiving apparatus for radiotelegraphy, and relates more particularly to automatic tickers whichwill operate in connection with tuned receiving circuits.

The object of my invention is to provide a ticker for an undampedelectric wave receiver which will be entirely automatic in its action,and which will be an improvement on the mechanically andelectrically'operated interrupters and tickers heretofore used.

Referring to the accompanying drawings:Figure 1, shows, in diagrammaticform, a radio-telegraph receiving station with my automatic tickerreceiver. Fig. 2, shows, in diagrammatic form, a radio-telegraphreceiving station with a modified form of my automatic ticker receiver.

In Fig. 1, A is an antenna, connected in series with an inductance coilL and an 'electromagnetically-aotuated variable condenser F G, andgrounded at E. The diaphragm G, forming one of the capacity areas of thecondenser F G, is made of iron or other magnetic material. The antennacircuit, by means of the coils L and L is coupled inductivoly with aclosed oscillatory circuit comprising the inductance coil L and thevariable condenser G. This circuit supplies unidirectional currentimpulses to the telephone P and the electromagnet M, by the action ofthe stopping condenser D and the rectifier R.

The operation of the'system is as follows :A continuous undamped wave isreceived, with which the antenna circuit A L F G E and theclosedoscillatory circuit L C are in resonance. The electromagnet Mistherefore energized and exerts an attractive for'e on the magnetdiaphragm G of the condenser F G. When G moves away from the othercapacity area F of this condenser,

the capacity of the condenser is altered, and

this change in capacity causes the antenna circuit to be thrown out ofresonance with the incoming electric waves, and the antenna circuitreceives so little energy, that the electromagnet M is practicallydenergized and no longer exerts an attraction on diaphragm G. The lattertherefore returns to its original position, the normal capacity of thecondenser F G is restored, and the antenna circult is again restored toresonance with the incoming electric waves. The receiving cir cuits aretherefore actuated and the electromagnet M is again energized. As longas the undamped electric waves continue to arrive, the same cycle ofoperations is repeated, at a frequency determined by the vibrat1onper-10d of diaphragm G, and there will be produced in the receivingtelephone P a sound corresponding to this vibration period Patented June2, 1914.

of diaphragm G. As the undamped electric waves generall have a frequencyabove the l mits of audibility, the telephone P will not respond audiblyto the action of the electric waves alone.

In Fig. 2, an antenna A is connected in series w1th an inductance coil Land an electromagnetically-operated multiple variable condenser F G F G,and is grounded at E The antenna circuit, by means of the coils L and Lis coupled inductively with a closed oscillatory circuit comprising theinductance coil L and the variable condenser C This circuit suppliesunidirec-' I tional current impulses to the telephone P and theelectromagnet M by the action of the stopping condenser D and therectifier R Electromagnet M actuates the diaphragm S of the resistancemicrophone T, which diaphragm is composed of iron or other magneticmaterial. Microphone T is v in circuit with battery B and electromagnetsM M M, and M These electromagnets actuate, respectively, the diaphragmsF F G andG which are composed of iron or other magnetic material, andwhich form the capacity areas of a multiple condenser, such as isdescribed in my applicationsfor U; S. Letters Patent, Serial No.702,175, filed June 7, 1912, and Serial No. 703,219, filed June 12,1912, where its advantages are set forth.

When the electromagnet M is energized on the reception of undampedelectric waves in resonance with the antenna and the closed oscillatecircuits, it exerts a force on diaphragm This alters the resistance ofmicrophone T and so changes the strength of the current which flows frombattery B through electromagnets M M M and M whose attractive force ondiaphragm F F G and G is therefore altered, and the distance betweencorresponding diaphragms F and Gr and F and G increased or diminished.In consequence, the capacity of the condenser F G F 2 G is changed, andthe antenna circuit is thrown out of resonance with the incomingelectric waves. The antenna circuit thereupon ceases to respond to theincoming waves and the closed oscillatory circuit L C and the circuitcontaining electromagnet M receive so little energy, that M isdemagnetized and ceases to attract diaphragm S, which returns to itsnormal position. The resistance of microphone T and the current throughelectromagnets M M M and M therefore resume their normal condition, andthe capacity of the con denser F G F G likewise becomes normal. Theantenna circuit is therefore again restored to resonance with theincoming electric waves, the receiving circuits are again actuated andthe electromagnet M is again energized, and the cycle of operations isrepeated, as long as the undamped electric waves continue to arrive, andsounds will therefore be produced in the receiving telephone P Byemploying the multiple condenser microphone, the advantage is gained ofsecuring a greater variation in the capacity of the antenna circuit,which can be thus thrown out of resonance more completely than with acondenser of the ordinary form.

I have not here shown transmitting apparat'us, but any suitable radiotransmitting apparatus, emitting undamped tuned electric waves, may beemployed in connection with the receiving apparatus shown.

Instead of changing the oscillatory period of the antenna circuit, I maychange the oscillatory period of the closed oscillatory circuit having arelatively small capacity so that the variations in themicrophone-condenser will produce a relatively large variation in thetotal capacity of the circuit, and various other changes andmodifications within the skill of those versed in the art, may be madein the particular apparatus shown and described herein, withoutdeparting from the spirit of my invention, provided the means set forthin the following claims be employed.

I claim as my invention 1. In a system of radio telegraphy, a tunedantenna circuit, including a variable condenser, a closed oscillatorycircuit normally in resonance with said antenna circuit, a circuitincluding a telephone and an electromagnet which receives currentimpulses from said oscillatory circuit, said electromagnet beingoperatively connected with said variable condenser so as to vary thecapacity of said condenser, substantially as described.

2. A radio telegraph receiving apparatus including a tuned oscillatorycircuit, automatic means for changing the oscillation period of saidcircuit, and means for making audible the changes in said circuit.

3. In a radio telegraph receiving station,

a tuned antenna circuit, means for automatically changing the capacityof said antenna circuit, means for automatically restoring said antennacircuit to its original condition, and means for making audible thesechanges in the antenna circuit.

4. A. radio'telegraph receiving apparatus including an antenna circuit,means for automatically varying the oscillation period of said antennacircuit at a rate Within the limits of audibility, and means for makingaudible these changes in the oscillation period of said antenna.

5. In a radio telegraph receiving station, a tuned receiving circuit,means for automatically changing the oscillation period of saidreceiving circuit, and means for making audible the changes in saidreceiving circuit.

This specification signed and witnessed August, A. D., 1912.

JOHN HAYS HAIVIMOND, JR.

Signed in the presence of-- MABEL J. COOPER, S. A. THORNTON.

